I am sure you have pondered this sort of idea but maybe don't realize the potential it may have, but having weekly events that involved interaction of the users can really give it a unique feel. In that, you can break out of the mold of other MMOs.
It would also add to the level of play this game could provide for maxed out characters, breathing life back into those often retired toons. What cooler way to keep a few veterans around than for higher leveled live events, and since we have adventure zones we could use those areas.
It's just an idea. You could also do a "chase" event where you have a named one running through town and those who catch him can get a reward, with his position being a random location.
Just food for thought.